The present invention relates in general to shock isolating lamp assemblies for automotive vehicles, particularly commercial vehicles such as trucks and the like, providing improved shock isolating and heat resistance properties, and more particularly to an improved shock isolating lamp assembly having a baseless cartridge bulb therein, for use particularly as safety lamps for on and off road motor vehicles, trailers, and the like, having improved shock and vibration dampening and heat resistance characteristics to allow longer life of the lamp assembly.
In the past, a number of arrangements have been proposed for shock mounting an incandescent lamp bulb within a lamp housing to be employed on motor vehicles, to reduce road shock and vibration effects on the filaments of the bulbs. As will be recognized by persons familiar with the art, automotive vehicles, and particularly trucks and similar commercial vehicles and trailers, are subject to recurrent road shocks in traveling over the highway and off road paths. These road shocks, transmitted through the frame of the vehicle, effect the relatively fragile filaments of the lamp bulbs in the marker, signaling and driving lamps of the vehicle, so that frequent breakage or disabling of such bulbs occurs due to the road shocks.
For many years, the electric light bulbs used in such signal, marker and driving lamps, were of the traditional construction wherein base portions, such as screw or bayonette bases, were provided forming the support base for the filament wires and supports therefor. Various shock mount arrangements have been proposed for such vehicle lamps involving the traditional base-type bulb, such as Dixon Pat. Nos. 3,059,104, 3,208,031, 3,222,512 and 3,115,307, showing use of a soft rubber receptacle or member to receive and support the base portion of the bulb for shock isolation purposes.
Other proposals have included resilient potting of an unbased lamp bulb within a receptacle portion of a lamp assembly suspended by flexible torque arms, proposed for example in U.S. Pat. No. 3,089,951, and use of a suspension structure including a pair of flexible arms extending laterally from opposite sides of a receptacle formation along serpentine paths curving about vertical axes and pivoted at their outer ends to the lamp housing have been proposed in U.S. Pat. No. 3,327,110, now U.S. Pat. No. Re. 30,498, assigned to the assignee of the present application, and similar U.S. Pat. Nos. 3,666,940, 4,241,371 and 4,282,566.
More recently, baseless cartridge lamps have been developed because of the great expense in manufacture of the base portions of the more traditional types of lamp bulbs, such as the screw or bayonette bases, relative to the remainder of the bulbs, and because the number of advantages arise from such a baseless cartridge lamp construction. In addition to the savings in mass producing such items, such as the assembly of such baseless-type cartridge bulbs with connectors for reliable and convenient mounting of the bulbs, the nature of the baseless cartridge bulb construction offers increased resistance to severe vibration and heavy shock loads, and permits use of reduced voltage levels needed to supply the bulb filament, which results in increasing filament life. While such baseless cartridge lamps, employed either as safety lamps or with dual filament construction permitting automotive tail and stop lamp illumination levels, have been previously used as automotive lamps, such baseless cartridge bulbs, to applicants' knowledge, have not been previously proposed for use in marker lamp, signaling lamp and driving lamp applications for trucks and similar vehicles subject to severe vibration, shock and heat problems.
An object of the present invention, therefore, is the provision of a novel shock absorbing bulb mount and lamp assembly for baseless cartridge lamps for use as marker, signaling and driving lamps of on and off road motor vehicles, trailers and the like, having novel bulb supporting arms of silicone rubber configurated and constructed to provide superior shock and vibration dampening characteristics allowing longer life due to increased resistance to vibration, shock and heat.
Another object of the present invention is the provision of a novel lamp assembly as described in the immediately preceding paragraph, wherein the mounting arms of silicone rubber for the baseless cartridge bulb connector/support ends, due to the unique shape and the flexibility of the silicone rubber under operating loads and conditions, achieves dampening of excessive shock impulses to the bulb filament.
Another object of the present invention is the provision of a shock mounted lamp assembly as described in either of the two preceding paragraphs, wherein a heat sink is incorporated in the form of a heat shield which serves to protect the silicone rubber shock mount arms from degradation and protects the plastic reflector portions of the housing structure from melting.
Another object of the present invention is the provision of a novel shock absorbing bulb mount and lamp assembly for baseless cartridge bulbs and the like as described in the immediately preceding paragraphs, which provide greater ease and economy of construction, increase bulb life by reducing the voltage applied to the filament through use of resistance wire, which can be radially mounted in any position in the normal vertical attitude, and which may be mounted in existing conventional mounting facilities of commercial vehicles and trailers without modification.
Other objects, advantages and capabilities of the present invention will become apparent from the following detailed description, taken in conjunction with the accompanying drawings illustrating a preferred embodiment of the invention.